Airbags and other pliable and inflatable restraints are being designed using releasable tethers to selectively modify the shape of the restraint, to provide the restraint with enhanced rigidity, and to control venting of the restraint during deployment. For example, in certain designs of airbag vent valve actuation mechanisms, the tether retention system maintains tension in the tether prior to release of the tether, and tension in the tether maintains a valve controlling an airbag vent in a closed condition. At some point during or after deployment of the inflatable device, tension in the tether may be relieved to permit actuation of the vent valve and subsequent release of airbag gases.
There is an ongoing need to minimize the costs involved in fabricating and installing tether retention systems. There is also an ongoing need to minimize the response times and maximize the reliability of such systems.